Ubuntu
libcgroup package

Oneiric fails to boot after upgrade from Natty if /etc/fstab contains a cgroup mount entry

Bug #893550 reported by Matthias Kretz
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
libcgroup (Ubuntu)
Fix Released
High
Serge Hallyn
Oneiric
Won't Fix
Undecided
Unassigned

Bug Description

I used LXC on this machine. Therefore I had to add a cgroup mount and added the recommended line
none /cgroup cgroup defaults 0 0
to /etc/fstab. This results in an unbootable system after upgrade to Oneiric. Apparently the boot just stops when it comes to mounting the entries in /etc/fstab.

I would expect that either
a) the system doesn't hang when this is added to /etc/fstab
b) on upgrade the package detects this condition and removes/comments the according line in /etc/fstab so that the system is still bootable.

SRU Justification:
1: Impact: failure to boot!
2: Development fix: don't start cgroup-lite if cgroups are mounted by fstab
3: Stable fix: same as development fix
4: Test case:
   a. add cgroup entry to /etc/fstab, i.e.
 mkdir /cgroup
    echo "cgroup /cgroup cgroup defaults 0 0" > /etc/fstab
   b. install cgroup-lite
   c. reboot
5: Regression potential: if the patch were wrong, we might end up with cgroup-lite
   not mounting cgroups when it should.

See original description

Related branches

lp:~serge-hallyn/ubuntu/precise/libcgroup/fix-cgrouplite-fstab
Stéphane Graber: Pending requested
Diff: 33 lines (+15/-0)
2 files modified
debian/cgroup-lite.cgroups-mount (+8/-0)
debian/changelog (+7/-0)
lp:ubuntu/precise/libcgroup
lp:ubuntu/oneiric-proposed/libcgroup
Revision history for this message
Serge Hallyn (serge-hallyn) wrote :

Thanks for submitting this bug.

I suspect this bug is actually in cgroup-lite. When I try to reproduce with libcgroup, cgroup-bin actually fails to install. Can you confirm (dpkg -l | grep cgroup) that cgroup-lite is the one installed? If so, I'll re-target.

Changed in libcgroup (Ubuntu):
importance: Undecided → High
status: New → Incomplete
Revision history for this message
Matthias Kretz (mkretz) wrote :

I confirm that cgroup-lite is installed. That's also the package which I reported the bug against in launchpad. Seems to be a launchpad feature to hide that information. ;-)

Revision history for this message
Serge Hallyn (serge-hallyn) wrote :

Ah, it (now?) comes from the same source package.

Thanks for the info. Question now is what to do about it.

I'm loath to have the cgroup-lite automatically removing fstab entries. The alternative is to fail install, or simply stop (but sucessfully) the upstart job, if a cgroup entry is in fstab.

I'm assigning temporarily to stgraber to get his opinion.

Changed in libcgroup (Ubuntu):
status: Incomplete → Opinion
status: Opinion → Confirmed
assignee: nobody → Stéphane Graber (stgraber)
Serge Hallyn (serge-hallyn)
Changed in libcgroup (Ubuntu):
assignee: Stéphane Graber (stgraber) → Serge Hallyn (serge-hallyn)
status: Confirmed → In Progress
Revision history for this message
Matthias Kretz (mkretz) wrote :

The patch looks like a good solution to me.

As admin I would appreciate a warning somewhere though. Probably best if it goes to syslog.

Revision history for this message
Serge Hallyn (serge-hallyn) wrote :

Good point - bzr tree updated so as to send a msg to syslog.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package libcgroup - 0.37.1-1ubuntu8

---------------
libcgroup (0.37.1-1ubuntu8) precise; urgency=low

  * debian/cgroup-lite.cgroups-mount: don't run if cgroups are mounted by
    fstab. (LP: #893550)
 -- Serge Hallyn <email address hidden> Tue, 22 Nov 2011 12:26:40 -0600

Changed in libcgroup (Ubuntu):
status: In Progress → Fix Released
Serge Hallyn (serge-hallyn)
description: updated
Revision history for this message
Martin Pitt (pitti) wrote : Please test proposed package

Hello Matthias, or anyone else affected,

Accepted libcgroup into oneiric-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

Changed in libcgroup (Ubuntu Oneiric):
status: New → Fix Committed
tags: added: verification-needed
Revision history for this message
Rodolphe (fedorage) wrote :

Hello,

I experienced the same bug from a distribution migration from 10.04 to 10.10; also with a fresh install on 10.10 and after "aptitude install cgroup-lite".

To fix it, i had to manually comment the cgroup mount point in /etc/fstab .

How can I help to test this package and validate the patch ?

Revision history for this message
Rodolphe (fedorage) wrote :

I made an error, it was from 11.10 to 11.10...

Serge Hallyn (serge-hallyn)
description: updated
Revision history for this message
Brian Murray (brian-murray) wrote : Verification still needed

The fix for this bug has been awaiting testing feedback in the -proposed repository for oneiric for more than 90 days. Please test this fix and update the bug appropriately with the results. In the event that the fix for this bug is still not verified 15 days from now, the package will be removed from the -proposed repository.

tags: added: removal-candidate
Revision history for this message
Matthias Kretz (mkretz) wrote :

Sorry, I won't be able to find the time to test this.

Revision history for this message
Brian Murray (brian-murray) wrote :

The version of libcgroup in oneiric-proposed has been removed as this bug report was not verified in a timely fashion.

tags: removed: verification-needed
tags: removed: removal-candidate
Changed in libcgroup (Ubuntu Oneiric):
status: Fix Committed → Triaged
Revision history for this message
Rolf Leggewie (r0lf) wrote :

oneiric has seen the end of its life and is no longer receiving any updates. Marking the oneiric task for this ticket as "Won't Fix".

Changed in libcgroup (Ubuntu Oneiric):
status: Triaged → Won't Fix
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